Last year a global disturbance of weather patterns disrupted harvests in many of
the world’s important agricultural areas. Worldwide production of soybeans, an
important source of protein for people and livestock alike, was not adversely
affected, however. Indeed, last year’s soybean crop was actually slightly larger than
average. Nevertheless, the weather phenomenon is probably responsible for a
recent increase in the world price of soybeans.
Which of the following, if true, provides the strongest justification for the
attribution of the increase in soybean prices to the weather phenomenon?
(A) Last year’s harvest of anchovies, which provide an important protein
source for livestock, was disrupted by the effects of the weather
phenomenon.
(B) Most countries that produce soybeans for export had above-average
harvests of a number of food crops other than soybeans last year.
(C) The world price of soybeans also rose several years ago, immediately
after an earlier occurrence of a similar global weather disturbance.
(D) Heavy rains attributable to the weather phenomenon improved grazing
pastures last year, allowing farmers in many parts of the world to reduce
their dependence on supplemental feed.
(E) Prior to last year, soybean prices had been falling for several years.

Answer is A .
But my doubt is  that we are concerned about Soybeans and in A we are talking about some other random crop .How is this relevant ?

OG Soln says

“If the weather disturbance reduced the anchovy harvest, and
anchovies provide protein for livestock just as soybeans do, then more
soybeans for livestock feed would be needed to compensate for the lack of
anchovies. The resulting increase in demand for soybeans could thus have
increased global soybean prices”

How can we assume that Soybean is the only crop to compensate for the lack of protein anchovy ?
I thought of B as it says the soy bean had below avg. production .So to meet the demand it had to increase the prices .
Any thoughts ?